Browsing by Issue Date, starting with "2016-12"
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- Copper(II) and iron(III) complexes with arylhydrazone of ethyl 2-cyanoacetate or formazan ligands as catalysts for oxidation of alcoholsPublication . Martins, Nuno; Mahmudov, Kamran T.; Guedes Da Silva, M. Fátima C.; Martins, Luisa; Pombeiro, ArmandoThe aquasoluble [Cu(1 kappa N,O-2:2 kappa O-HL1)(S)](2) [S = CH3OH (1), (CH3)(2)NCHO (2)] and [Cu(kappa N-HL1)(en)(2)]center dot CH3OH center dot H2O (3) Cu-II complexes were prepared by the reaction of Cu-II nitrate hydrate with the new ligand (E/Z)-4-(2-(1-cyano-2-ethoxy-2-oxoethylidene)hydrazinyl)-3-hydroxybenzoic acid (H3L1), in the presence (for 3) or absence (for 1 and 2) of ethylenediamine (en), while the Fe-III complex [Fe(kappa N-3-HL2)(2)] (4) was isolated by treatment of iron(III) chloride hexahydrate with the new ligand (1E,1E)-N',2-di(1H-1,2,4-triazol-3-yl)diazenecarbohydrazonoyl cyanide (H3L2), and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. Cooperative E,Z -> E isomerization of H3L1, induced by coordination and ionic interactions, occurs upon interaction with Cu-II in the presence of en. Complexes 1-4 act as catalyst precursors for the solvent-free microwave (MW) assisted selective oxidation of primary or secondary alcohols and diols to the corresponding aldehydes, ketones and diketones, respectively, with yields in the 5-99% range (TONs up to 4.96 x 10(2)) after 60 min of MW irradiation at 120 degrees C. The influence of temperature, time and organic radicals was studied and also the regioselective oxidation of the catalytic systems involving the primary and secondary alcohols.
- Developing an Event-Tree Probabilistic Tsunami Inundation Model for NE Atlantic Coasts: Application to a Case StudyPublication . Omira, Rachid; Matias, Luís; Baptista, Maria Ana Carvalho VianaThis study constitutes a preliminary assessment of probabilistic tsunami inundation in the NE Atlantic region. We developed an event-tree approach to calculate the likelihood of tsunami flood occurrence and exceedance of a specific near-shore wave height for a given exposure time. Only tsunamis of tectonic origin are considered here, taking into account local, regional, and far-field sources. The approach used here consists of an event-tree method that gathers probability models for seismic sources, tsunami numerical modeling, and statistical methods. It also includes a treatment of aleatoric uncertainties related to source location and tidal stage. Epistemic uncertainties are not addressed in this study. The methodology is applied to the coastal test-site of Sines located in the NE Atlantic coast of Portugal. We derive probabilistic high-resolution maximum wave amplitudes and flood distributions for the study test-site considering 100- and 500-year exposure times. We find that the probability that maximum wave amplitude exceeds 1 m somewhere along the Sines coasts reaches about 60 % for an exposure time of 100 years and is up to 97 % for an exposure time of 500 years. The probability of inundation occurrence (flow depth > 0 m) varies between 10 % and 57 %, and from 20 % up to 95 % for 100- and 500-year exposure times, respectively. No validation has been performed here with historical tsunamis. This paper illustrates a methodology through a case study, which is not an operational assessment.
- Promover o acesso aberto com o Open Journal System: duas instituições, duas realidadesPublication . Seguro-de-Carvalho, Paula; Teófilo, RuiDevido às alterações tecnológicas que ocorreram nos últimos anos foram introduzidas novas formas de adquirir, armazenar e transmitir a ciência. As instituições de ensino superior que têm revistas científicas procuram divulgá-las e dar-lhes visibilidade. Para o fazer muitas têm recorrido à utilização do Open Journal System (OJS), desenvolvido pelo Public Knowledge Project. Usando este sistema foi possível criar uma plataforma independente para a revista Saúde & Tecnologia, da ESTeSL, e para a revista Da Investigação às Práticas, da ESELx. O objetivo para a implementação do sistema foi facilitar as tarefas dos editores, dar maior visibilidade às revistas e disponibilizá-las em plataformas internacionais. Ambas as Escolas decidiram usar o OJS para a realização desta tarefa e, neste momento, as duas revistas dispõem de um espaço independente onde estão alojados os números já editados. A ESTeSL também disponibiliza a sua revista no Directory of Open Access Journals (DOAJ) e a ESELx na Scientific Electronic Library Online (SciELO) que, por sua vez, assegura o processo de submissão ao DOAJ. As vantagens da adoção desta plataforma são a disponibilização de uma plataforma web acessível a qualquer um dos elementos envolvidos no processo editorial, a qualquer hora e em qualquer lugar.
- A previsão do fracasso empresarial utilizando a análise discriminante e o logit no setor hoteleiro portuguêsPublication . Teixeira, José Manuel Pereira; Silva, Amélia Ferreira da; Basto, Mário; Dos Santos, Maria José Palma LampreiaO turismo é um setor em forte expansão em Portugal e com um importante contributo na economia portuguesa. Por isso, o equilíbrio financeiro das empresas neste setor reveste-se da maior relevância, quer para os agentes económicos, quer para os decisores políticos. Apesar disso, não existem em Portugal trabalhos de investigação que analisem o fracasso empresarial no setor da hotelaria. O objetivo principal deste estudo é propor um modelo de antecipação do fracasso empresarial, especificamente desenvolvido para o setor hoteleiro português. Para esse efeito, utilizamos uma amostra de empresas do sector à qual aplicamos a análise discriminante e a técnica logit. Os resultados obtidos mostram um elevado grau de ajustamento do modelo aos dados e indicam que o modelo utilizado constitui um importante contributo na definição de políticas macroeconómicas e programas de apoio ao desenvolvimento do turismo, sendo igualmente relevantes para as decisões de investidores e credores.
- Apreciação ética de projectos de investigação em saúde: uma reflexão situada a propósito da ética de investigação em ciências sociaisPublication . Raposo, Hélder AntónioTomando como ponto de partida uma experiência de colaboração numa comissão de ética de saúde, a presente proposta procura constituir-se como um exercício reflexivo sobre o percurso de participação decorrente do vínculo formal a uma estrutura desta natureza. No entanto, mais do que apenas apresentar um testemunho pessoal que ponha em evidência a visão de um sociólogo relativamente à integração e participação num órgão colegial e multidisciplinar orientado para as questões da saúde, ensaio um exercício analítico orientado para a compreensão e discussão das particularidades do papel e da acção desta estrutura em matéria de apreciação e deliberação ética de projectos de investigação.
- Performance of a VDFLL GNSS receiver architecture in presence of interferencePublication . Sousa, Fernando; Nunes, FernandoWe discuss the advantages of using a vector delay/frequency-locked loop (VDFLL) architecture for GNSS receivers operating in scenarios disturbed by radio-frequency interference. Narrowband (sinusoidal) and wideband (chirp) interference signals are considered in the analysis. The VDFLL is constituted by a bank of code and frequency discriminators feeding a central extended Kalman filter that estimates the receiver's position, velocity, and clock bias. Simulation results are obtained using sine-phase binary offset carrier BOCs(1,1) modulation. The results are compared with the theoretical performance determined by the effective signal power to noise density ratio.
- Deriving an indoor environmental index for portuguese office buildingsPublication . Gomes, João; Esteves, Hélder M. S.In 2002, the European Commission (EU) issued a Directive aiming to reduce the energy consumption of buildings, which was adopted by the EU member states and came into force in 2006. Portugal adopted it by issuing law decrees in 2006 which considered not only the energy saving aspects but also additional specific measures aiming to protect indoor air quality (IAQ). This new legislation is now being enforced, and it will be necessary to define compliance acceptance levels for the prescribed indoor air limits. The use of comfort or environmental indexes could be of considerable help to ameliorate the evaluation of IAQ. This paper presents a proposal of an index regarding IAQ which considers both the aspects of thermal comfort and non-toxicity. The proposed index was calculated for offices of several European countries, available from previous studies and for Portugal as well. Bearing in mind there is few existing data, this study is consistent with the proposed index, as the obtained values are similar to Greece, which has several similarities with the Portuguese situation.
- Using the finite element method to understand calculusPublication . Rodrigues, José Alberto; Loja, Amélia; Barbosa, JoaquimThis paper presents a complementary, alternative teaching and learning methodology based on the use of the finite element method to illustrate mathematical models and to explore their (numerical) solutions in the context of vector calculus properties understanding. This methodology is illustrated via a set of examples focused on specific engineering problems, but its scope can also be widened to other scientific areas. The examples presented on this paper allow concluding that this approach may be an interesting way to re-think and complement the perspective usually considered in the transmission of mathematical concepts. The use of a freeware finite element method computational package, FreeFEM++ may also be an important issue to stimulate the dissemination of this phenomena modelling and comprehension approach.
- Família empresária e competências empreendedorasPublication . Rodrigues, JorgeO modelo ideal de família preconizado na modernidade enfatizava o amor romântico, o matrimónio ideal e o afeto como base da vida familiar. Hoje, a ênfase parece estar no bem-estar do momento, sem importar o passado. Assim, o objetivo deste artigo é o de procurar compreender as relações entre as competências empreendedoras assentes no individualismo e a composição da família empresária, a cada momento. Cada geração tende a dispersar pelos seus públicos o acervo de património herdado, com a maioria das empresas familiares que desaparecem a terem como causa principal os conflitos familiares não resolvidos. Assim, através de uma pesquisa exploratória sobre as competências empreendedoras e a teoria baseada nos recursos, procurou-se contribuir para a definição do conceito de família empresária e o modo como esta depende e influencia os seus membros.
- Automated rf-PERTE system for room temperature deposition of TCO coatingsPublication . Fernandes, M.; Vygranenko, Y.; Vieira, M.; Lavareda, G.; Carvalho, C. Nunes de; Amaral, A.In this work we present a fully automated plasma-enhanced reactive thermal evaporation system (rf-PERTE) that can be used for the deposition of transparent metal oxide films without intentional heating of the substrate. The system and developed software enables the full control over critical deposition conditions such as mass flow of oxygen, process pressure, current flowing through crucible and rf-power. These parameters are automatically adjusted during the deposition thus keeping them in a narrow process window. This way, highly transparent and conductive coating can be deposited with a high degree of reproducibility of the optical and electrical characteristics. The resistivity of 9×10-4 Ω-cm and the peak transmittance of 90% in the visible spectral range were achieved for indium oxide films deposited on glass substrates. This technique is also suitable for the deposition of transparent conducting coatings in a wide range of plastic materials for flexible solar cells. In particular, we have successfully deposited indium oxide on PEN (polyethylene naphthalate) sheets with electrical and optical properties approaching the ones for films on glass.